Combined Experimental and Theoretical Study of the Transient IR Spectroscopy of 7-Hydroxyquinoline in the First Electronically Excited Singlet State

2016 ◽  
Vol 120 (47) ◽  
pp. 9378-9389 ◽  
Author(s):  
Felix Hoffmann ◽  
Maria Ekimova ◽  
Gül Bekçioğlu-Neff ◽  
Erik T. J. Nibbering ◽  
Daniel Sebastiani
Keyword(s):  
Ir Spectroscopy ◽  
Theoretical Study ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Electronically Excited

Violation of Hund's multiplicity rule in the electronically excited states of conjugated hydrocarbons

1985 ◽  
Vol 63 (7) ◽  
pp. 1572-1579 ◽  
Author(s):  
Shiro Koseki ◽  
Takeshi Nakajima ◽  
Azumao Toyota
Keyword(s):  
Triplet State ◽  
Excited States ◽  
Singlet State ◽  
Basis Set ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Electronically Excited States ◽  
Conjugated Hydrocarbons ◽  
Electronically Excited ◽  
Linear Polyenes

Violation of Hund's multiplicity rule in the electronically excited states of conjugated hydrocarbons is studied by using the Pariser–Parr–Pople type SCF MO method and the abinitio MO method with STO-3G basis set, both methods being augmented by CI-type treatments. It is shown that for symmetrical structures (D2h) of the nonalternant hydrocarbons, propalene, pentalene, and heptalene, the lowest excited singlet state is energetically lower than the corresponding triplet state. This is mainly due to the spin polarization (SP) effects. For D2h, structures of pentalene and heptalene the open-shell excited singlet state is predicted to be lower in energy than the closed-shell state, with the result that the former is really the ground state. Further, calculations made by including electron correlation effects reveal that in linear polyenes and polyacenes, the lowest excited singlet "minus" state (using Pariser's classification of the alternancy symmetry species) is lower in energy than the corresponding triplet state. The energy lowering of the singlet "minus" state in linear polyenes is due mostly to the mixing with the doubly excited configurations (mm → nn), while the considerable part of it in polyacenes is due to the SP effects.

Aggregation controlled photoluminescence of hexaazatri-naphthylene (HATN) – an experimental and theoretical study

2020 ◽  
Vol 22 (27) ◽  
pp. 15437-15447
Author(s):  
Olaf Morawski ◽  
Jerzy Karpiuk ◽  
Paweł Gawryś ◽  
Andrzej L. Sobolewski
Keyword(s):  
Solid State ◽  
Triplet State ◽  
Theoretical Study ◽  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet

Photophysics of hexaazatrinaphthylene (HATN) in solution and in the solid state is determined by the nπ* character of its lowest excited singlet state and by the ππ* character of the first triplet state, and changes upon aggregation.

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